Your moveset looks good, but think about Quick Attack > Protect. If a Timburr or Meinfoo comes in Rattata is mouse meat, Quick Attack would give him a chance to take them down, but you'd lose your Protect, which honestly would be useless after you used it the first time, but it is nice for activating dat Flame Orb. But lose the HP EVs, if he has 19 EVs the Flame Orb will take away less HP. Another set Rattata is capable of running would be a Choice Scarf Hustle set. His accuracy would be lower, of course but he gets a nice power boost and with a scarf would make him a great revenge killer.
Rattata @ Choice Scarf
EVs: 36 HP / 236 Atk / 180 Spe
Jolly / Adamant Nature
- Flame Wheel
Return is your STAB, U-turn is for scouting and revenge killing, Flame Wheel deals with Steel types like Ferroseed, Bronzor, Klink, and Pawniard, while Crunch takes down Ghastly, Misdreavus, and Drifloon.